Based on the great wizard Merlin of legend, he is the main character Shin's (adoptive) grandfather in the new world Shin finds himself in. Having been heralded as the great magician, he teaches Shin many forms of magic as he grows up, but Shin ultimately finds his own ways to surpass even his grandfather. However, Merlin has been shown to be able to replicate just about any magic Shin is capable of creating. His sheer destructive power has not been shown yet, but considering his reputation, it is likely more or less just as large as Shin's.